The invention relates to a turbine housing for an exhaust gas turbocharger of an internal combustion engine including at least one spiral channel structure, and to an exhaust gas turbocharger including such a turbine housing as well as to a method for producing a turbine housing for an exhaust gas turbocharger.
Due to the continuous tightening of the emission limit values, for example the NOx and soot emission values, the demands on exhaust gas turbochargers or charged internal combustion engines also increase. Thus, for example, there are growing demands with regard to the charge pressure over the medium to high load operations of the internal combustion engine, as a result of which exhaust gas turbochargers have to be decreased more and more in size. The required high turbine performances of exhaust gas turbochargers are in other words realized by an increase of the back pressure capability or by the reduction of the flow volume reserve of the exhaust gas turbochargers in cooperation with the respective internal combustion engine, which however leads to low efficiencies. A further influencing of the performance of exhaust gas turbochargers occurs by exhaust gas after-treatment systems arranged in the exhaust gas tract downstream of the turbine as for example soot filters, catalysts or SCR systems. These exhaust gas after-treatment systems lead to a pressure increase at an exhaust gas outlet of the turbine housing or of the exhaust gas turbocharger. This again leads to a reduction of the turbine pressure drop describing the performance of the exhaust gas turbocharger. The turbine pressure drop can be determined as the quotient of a pressure in front of the turbine wheel or an exhaust gas inlet of the turbine housing and a pressure behind the turbine wheel or an exhaust gas outlet of the turbine housing. Also for this reason, the turbine size has to be designed for smaller flow-through values and thus for lower efficiencies in order to be able to satisfy the performance requirement of the compressor side of the exhaust gas turbocharger. A certain improvement in particular for internal combustion engines with exhaust gas recirculation systems is hereby offered by conventional exhaust gas turbochargers, whose turbine housings comprise two spiral channels through which exhaust gas can flow independently and that are usually formed in an asymmetric manner. The spiral channels are respectively coupled to different exhaust gas lines of an exhaust gas tract of the internal combustion engine. However, the spiral channels of these turbine housings have also reached spiral sizes in the meantime which result in very high flow losses by means of wall frictions and due to the small dimensions. Additionally, certain problems exist with regard to the exhaust gas recirculation capability in connection with the necessary combustion air of the internal combustion engine in particular in the lower to the medium speed range.
A particular problem resides in the fact that the known turbine housings or the exhaust gas turbochargers provided with these housings have to be adapted in a constructively elaborate manner, in order to be able to be utilized with satisfactory efficiencies for different types of internal combustion engines. Hereby, large production, storage holding and part costs are encountered.
It is thus the object of the present invention to provide a turbine housing or an exhaust gas turbocharger with such a turbine housing, which can be adapted in a simple and cost-efficient manner to different types of internal combustion engines.